My keyboard goes 'crazy' sometimes (i.e. CTRL key stuck, arrow keys not responding, unable to write text, etc) when I press the mentioned combinations. When this happens, I try pressing ALT or CTRL keys to put it back to normal. When that doesn't work, I try pressing random keys to fix it.

I never press more than 3 keys at the same time.
I have disabled sticky keys in Windows and my keyboard's vendor is Microsoft.

Is there any particular reason why this happens? If so, how can I avoid this?

Edit: To be more specific.

I use arrow keys to move (UP, DOWN, LEFT and RIGHT)

I can press CTRL key while moving (CTRL+UP, CTRL+DOWN, CTRL+LEFT and CTRL+RIGHT)

I can use game shortcuts with different combinations to cast spells (e.g. F11, CTRL+F12, SHIFT+F10, ALT+F1)

My issue:

Sometimes when using a combo (point 3). My keyboard appeards to be 'frozen'. For instance, pressing F12 sends instead the CTRL+F12 command (I can tell this by the action it does). I'm not able to type in game chat or send a single F12 command. It appears as the CTRL key is pressed continuosly, hence not letting me do any other action at all.

The game is not full screen, Mouse appears to be working fine. just can't switch windows when I encounter this problem.

I wouldn't recommend copy and pasting this to stack overflow. This is not a programming question. Perhaps you are simply using too many resources while gaming and the keyboard is lagging? Are there any other signs of things slowing down other than the keyboard?
– Eric FApr 8 '16 at 18:28

Do you have any way of verifying that everything else is running normal? Does it only happen in a particular game or all games?
– Eric FApr 8 '16 at 18:34

It only happens on this game. Users have not reported this issue. Computer does not freeze/lag. I believe it might be related with 'F' keys
– user3546771Apr 8 '16 at 19:01

"This game" = What? Is it full screen? This is probably a restatement of Erics question, but do the key inputs only "go crazy" in the game window and are fine system-wide? (Alt-tab to notepad and try typing etc.
– YorikApr 8 '16 at 19:22